Tuning arrangement for wireless receivers



Aug. 7, 1945. c. L. RICHARDS 2,381,227

' TUNING ARRANGEMENT FOR WIRELESS RECEIVERS I Filed Feb. '7, 1944 2 sheets-sheet "1 [I2 U822 for c L, HUGH/W06 Aug. 7,1945. c. L. RICHARDS TUNING ARRANGEMENT FOR WIRELESS RECEIVERS Filed Feb. 7, 1944 2 sheets-sheet 2 I I I I Invenior C4 LJQVCY/ARDQ fl iforney Patented Aug. 4 7, 1945 UNITED STATES:

TUNTNG ARRANGEMENT roa WIRELESS aacsrvras Claude Langdon Richards, London, England, as-

sls'nor to The Hartford National Bank and Trust Company, Hartford, Conn., as trustee Application February i, 1944, Serial No. 521,427

In Great Britain October 1, 1942 Claims. (01. 74-10) This invention relates to tuning arrangements for wireless receivers and has for its object to provide a tuningarrangement the manipulation of which requires very little concentration on the part of theuser, but nevertheless enables rapid 5 tuning to a desired station. The invention is thus particularly well adapted for wireless receivers designed for usein motor cars With this object in view, the tuning arrangement according to the present inventi n' comprises a member co pled with the ma tuning condenser or other tuning device, The said member is mounted for translational movement as well as for rotational movement without translation, the coupling being such-that the translation causes coarse tuning'and the rotation causes fine tuning. The tuning member consists of a rod journaled in an arm so as to move therewith in a translatory movement, while being capable of independent rotation in its journals. The arm is associated with a plurality-of retaining devices distributed (not necessarily uniformly) over the scale thus tending to hold the arm in any one of a corresponding number of positions providing a preliminary or coarse tuning.

In order that the invention may be more readily understood, reference is made to, the accompanying drawings which show a preferred embodiment of the invention and inwhich,

Fig. 1 is a perspective view showing the tuning so arrangement dissociated from the wireless re-' ceiver,

Fig. 2 is a fragmentary cross-section substantially along the line IIH of Fig. 1,

the shaft which is tobe rotated for altering the tuning of the receiver is shown at 33. Usually this shaft constitutes or is connected with the shaft of the main tuning condenser of the receiver. However, any other form of tuning element for the receiver, suchas variable inductance, may be employed. The invention is not to be regarded, as limited to any particular type of receiver or tuning element therefor. Fixedto the shaft'33 is a pulley 34 whichis connected by a cord 4 to the pulley 3 of the arrangement shown in greater detail in Figs. 1' and 2 and hereinafter more fully described. The pulley 3 is secured to a shaft 2 which is joumaled in a bearing plate 35 5 rigidly secured to or forming a main frame element ofthe cabinet or housing 30. The shaft 2 passes freely through an arm] which is spaced from the bearing plate 35 by a washer or distance piece" which preferably constitutes an mu 6 0 friction bearing facilitating pivotal movement of the arm i about the axis defined by the shaft 2. Referring now more particularly to Figs. 1 and 2, the arm I is provided at opposite ends with upstanding lugs 8 and I in which a rod 5 is journaled. The forward end of the rod 5 projects from the cabinet 30 and carries a knob 8 to facilitate manipulation. Adjacent the shaft 2 the arm I is provided with an upstanding side plate 9 with inwardly turned ears at either end. Joumaled in this plate 9 are two jockey pulleys 10, H around which passes a cord l3 the erids 0f which are wrapped around and anchored to the rod 5. The I cord i3 also passes around a pulley l2 secured to the top of the shaft -2. The cord I3 is associated with the rods in such manner that on rotating the latter in its journals one end of the cord is wound on the rod and the other end is correspondingly unwound. Thus the direction oi-rotation imparted to the pulley I! by the cord I3 is determined by the direction in which the rod 5 is rotated in its journals 6, l by manipulation of the knob 8. If the knob 8 is held against rotation, the pulley I2 is likewise held stationary in relation to the arm I.

Carried at the forward end of the arm I, e; g. m

on the mg I is a pointer l4 which moves over a scale l5 provided on the cabinet 30 and serves to show the setting of the tuning.

To permit rapid setting of the arm I to one 4 a slot ii! are notched plates 11. I8, hereinafter termed click plates. The click plate I! isflat whereas the click plate l8 has a stepped end, so

that two click plates can be secured at a closer I I spacing than corresponds to the width of the heads of the click plates. A closer spacing can be achieved by securing the -click plates alternately on the upper and lower sides of thebar i6. Co-operating with the click-plates l1, i8 is a pin 25 carried on a lever 2| pivoted at 22 to the lug I on the arm I and 'urgedby a spring 23 to impel the pin 25 into engagement with the clickplates l1, L8. A stop 24 on the lug 1 serves to limit themovement of the pin 25 towards the bar It I The arm I is preferably made from sheet metal, I

the bracket 9 for the jockey pulleys I0, I I, and the lugs 6 and I in which the rod 5 is journaled being formed by bending up portions of the sheet metal blank.

In the drawings, no means are shown for keeping the cords 4; l3 taut. Any conventional means may be provided for this pu p se. In the case of the cord I! one or both of the pulleys I 0, ll

maybe movably mounted and spring loaded so asto maintain the requisite tension in the cord.

The arrangement as described and illustrated operates in the following manner:

By means of the click mechanism (l1, l8, 2-5) the rod 5 and arm I can be releasably detained in any one of a number of predetermined positions corresponding subtstantially to the tuning for selected transmitters. If the selected transmitter is not exactly in tune, fine tuning adjustment is effected by rotating the knob 8 while the arm I remains stationary in the position de, termined by the click mechanism. Ifhe engagement of the pin 25 in the click plates I1, I8 is sufficiently positive to prevent accidental disengagement, but is not such as to prevent the displacement of the arm I from one tuning position to another by theuser.

I claim:

1. In awireless receiver, a tunable element incorporated in the receiver, a shaft in driving conmember interconnecting said rod member and driver member'and producing rotation of the driver member relative to the arm upon rotation driver member and said arm-member being independently rotatable about a common axis, a sta tionary member fixed in relation to the said axis and parallel to the plane of rotation of said driver and arm member, a plurality of plate members adjustably mounted on said stationary member, said plates each having a notch therein, detent means comprising a leverelement secured to said nection with the tunable element, an arm pivtion in relationto the arm except on rotation of the rod.

2. An apparatus for adjusting the position of a tunable element comprising, adriver member for the tunable element, an arm member, said driver member and said arm member being independently rotatable about a common axis, means to hold the arm member in predetermined positions about the axis of the said arm member corresponding to coarse adjustments of the tunable element, 'a rod member rotatable about its longitudinal axis, mounted 'on said arm member and rotatable about said common axis in synchronism with the arm member, and a coupling member fixedly positioning the arm and the driver member re1ative toeach other upon rotation of the arm member, said coupling member interconnecting said rod member and driver member and producing rotation of the driver member relative to thearm upon rotation of the rod member about its arm member, a Pin member mounted on said lever element and a spring member engaging said arm and said lever to urge the pin against said plate members and to engage the pin and the notches to thereby hold the arm in predetermined positions about the axis of the, arm, said positions being fixed by the notches in said plates and corresponding to coarse adjustments of the tunable element, a rod member rotatable about its longitudinal axis, mounted on said arm member and rotatable about said common axis in synchronis'm with the arm member, and a coupling member fixedly positioning .the arm and the driver .member relative to each other upon rotation of the arm member, said coupling member interconnecting said rod member and driver member and producing rotation of the driver member relative to the arm upon rotation of the rod member about its said longitudinal axis corresponding to fine adjustment of the tunable element.

5. An apparatus for adjusting the position of a tunable element comprising, a driver member for the tunable element, an arm member in the form of a sheet metal stamping, integral bearing brackets at opposite ends of the arm member,

said driver member and said arm member being independently rotatable about a common axis, a stationary member fixed in relation to. thesaid axis and parallel to the plane of. rotation of said driver and arm members, a plurality of plate members adjustably mounted on said stationary member, said plates each having a notch therein,

said longitudinal axis corresponding to fine adjustment of the tunable element. l

3. An apparatus for adjusting the position .of a'tunable elementcomprising, a driver member for the 'tunableielement, an arm, member, said said arm member and rotatable'about said com-' inon axis in synchronism with the arm member,

and acoupling member fixedly positioning the arm and the driver member relative to each other upon rotation of the member, said coupling means comprising a lever element secured to said arm member, a pin mounted on said lever element and a spring member engaging said am and said lever to urge the pin against said plate members and to engage the pin and the notches to thereby hold the arm in predetermined positions about the axis 01' the rotatable arm member, said positions being fixed by the notches in said plates and corresponding to coarse adjustments of the tunable element, a rod member rotatable about its longitudinal axis mounted on said arm memher in said brackets and rotatable about said common axis in synchronism with the arm member, and a coupling member fixedly positioning the arm and the driver member relative to each other upon rotation of the arm member, said' coupling member interconnecting said rod member and driver member and producing rotation oi the driver member relative to the arm upon rotation oi the rod member about its said longitudinal axis corresponding to fine adjustment of the ,tunableelement.

CLAUDE monorznrc .1 

